Spring-calculator.



H. A. SGHWAGER.

SPRING CALCULATOR.

APPLICATION FILED AUG.1,1914.

Patented Dec. 29, AQUA.

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HENJRJY ALFRED SCHW'AGER, OF DETROIT, MICHIGAN.

SPRING-CALCULATOR.

Application filed August 1, 1914.

To fl/ /r/m//iy it may concer/i le it known that I, HnXnY ALrni-:n cnwacnn, citizen ot' the United States, residing at Detroit. county ot' llvayne` State of ilichgan, have invented a certain new and useful improvement in Spring-Calculators, and declare the tollowing to be a full. clear, and exact description ot' the same, such as will enable others skilled in the art to which it pertains to make and use the saine, ret'erence being had to the accompanying drawings, which form a part of this specilication.

My invention relates to a computing chart and is especially designed for the calculation of helical springs.

The object ot' this invention is to provide a simple, easily readable, and comparatively inexpensive device, adapted to indicate the `safe load" of a helical spring constructed of either round or square wire oil standard gage, of ditl'erent materials, and ot' any required pitch diameter: and the deiiection per coil. By its use springs mayY be formed to carry a certain load. with a predetermined O"age of wire, and pitch diameter. or the "saie load" of a spring already constructed may be' ascertained. the material, gage of wire, and pitch diameter being known.

@ther advantages and improvements will hereafter appear.

"4 the drawings: Figure l. is a plan view o the device indicatingr its double swinging arm and the small disk engaged therewith, in one ot' its adjusted positions. Fig. 2, is a central cross sectional view through the l l s and the swinging arm.

ie'lierring to the letters Vof reference placed upon the drawings, A, denotes an l.-

` shaped or double indicating arm formed of celluloid or other transparent material.

B indicates a relatively small disk provit ed with radial lines L, representing different gages ot round and square steel, bronze and brass wire.

C is a plug serving as a pivotfor the double arm and disk B, which are in turn connected together to operate. as a single unit by the rivet or dowel pin D.

il indicates an annular disk mounted upon a base plate H, concentric with the disk B.

F denotes a spring washer beneath the disk B the projecting edge of which bears against the plate Ha.

G, is a illister hand screw engaging the Specification of Letters Patent.

- Talented Dec. 29, wist.

Serial No. 854,464.

plug C, and bearing against the spring washer which serves to maintain the disks and the double indicating arm in operative relation.

z, denotes a plurality oi' radial lines on the disk H registering with the radial lines o. on the disk B: representingr pitch diameters which the various wiresI indicated on the disk B may be coiled to form springs adapted for certain loads.

fr, y, denotes hair lines on the double arm L., lespectively indicating "load" and de i'iection.

H, H2, H3, Ht. are concentric columns denoting the load given in pounds. figured to stresses ot' 40,000. 50.000, 50,000 and TtLOOO pounds per square inch.

The dellection per coil is given in tigured to a stress of, (u00 lbs. per inch for steel wire. T0000 lbs. per inch tor music wire.` 40000 lbs. per inch for bronze wire, 230000 lbs. per inch for brass wire.

Each size of wire mentioned on disk B has a concentric column l. l. etc., on disk H where the value of dcllection is given. The wire sizes as given on disk B are eX- pressed in what is known as the llvashlnirn t Moen standard gage for round steel. and in Jfractions of an inch for square steel. .lt will he obvious however that any standard gage" may be employed.

The calculator as set atl'ords a reading for .fi-5% wire, which registers with alinch pitch diameter, and for which setting the hair lines on arm indicates a load ot' S5 lbs. when stressed at H0000 lbs. per square inch, 99.2 when stressed to T0000 lbs., 70.5 when stressed to 50000 lbs., 56.4' when stressed to 40000 lbs.

(S0000 lhs. per square inch is generally taken as the salie load for common spring steel. rl`he load under such stress is S5 lbs. The deflection per coil for this load can be found in the deflection column of wire. and is 1.175 inches. Now if a spring of the same dimensions, but ot' bronze inst aid ot' steel, were made. the sat'e load may be read in the column ot' 40ml() lbs. stress, and the Aanswer being 5T lbs., for which load the same deflection ot 1.173 inches isi-indicated.

To determine what the opportunities are with a steel spring loaded to 85 lbs., beginning with :bl-21 we lind it registering with l inch pitch diameter; #l with approximately 3-3/16; #5 at 2-15/32; #G at inches, square square square square but due to the small space available on the drawing, it is impracticable to incorporate all of the figures. lt will also be obvious that the iigures on the indicator arm denote the wire number or gage, and are designed to register with the respective con- -centric rows of graduations on the stationary disk denoting deflection.

. Having thus described myinventionwhat lclaim .is

, l. In a device of the character described," a rotatable radially graduated disk, an indicator comprising two arms in spaced relatiorAk adapted to rotate with the disk as a single unit, and a stationary disk having a4 plurality of sets of graduations, with certain of which the graduations on the rotar 'table disk and the respective swinging arms of the indicator are adapted to register;

2. ln a device of the character described, a rotatable disk provided with radial graduations denoting metal gage, a stationary disk concentric to the rotatable disk having a plurality of radial Cgraduations denoting pitch diameter adapte to register With the radial graduations of the rotatable disk, together with other groups ofradial graduations in concentric rows denoting respectively load and spring deiiections, and

ari indicatbrnlformed of 4transparent material vconnected with the rotatable disk to rotate "therewith, comprising two arms in spaced relation to each other having indicator lines "adapted to register with the graduations on g the stationary disk, one ot said arms provided Withrows of numerals indicating Wire gages adapted to register with the concentric rows of graduations on the fixed disk denoting deflection.

3. In a mechanical calculating device, the combination of a rotatable, radially graduated disk, a transparent indicator secured to said disk and rotatable therewith comprising two'arm's, held .in spaced relation, an

annular stationary disk concentric with the rota-table disk having radial lines adapted to registerL-With the radial lines of the rotatable disk and with a plurality of groups of graduations ,in concentric rows, one arm of said indicator having numerals in rows adapted to register with the rows of graduations on the stationary disk, each arm having also indicator lines adapted to register Withthe respective graduations on the stationary disk, whereby one arm may indicate values obtainable through the registration of factors represented by the radial lines on the' movable disk with other factors represented by the radial lines on the stationary disk, the other arm indicating values obtainable through the registration ofthe two factors and the reading on the first named arm.

In testimony whereof I sign this specilication in the presence of two witnesses.

HENRY ALFRED SCHWAGER. Witnesses:

5.12. THoMas,

FRITZ 

